Fuse extractor for use with fuse links having a flexible lead extending therefrom

ABSTRACT

A fuse extractor assembly for use with a fuse link having a flexible lead extending therefrom and wherein the fuse link is mounted within a fuse tube. The assembly includes a base member fixedly secured to one end of the fuse tube and having an opening therein so that the flexible lead extends from the fuse tube through the opening. An extension rod slidably engages the base member in a first bore therein, and extends longitudinally of the fuse tube. A flat spring is fastened at one of its ends to a spring drum and wound thereabout. The other end of the spring is fastened to the extended end of the extension rod. The flexible lead is fed through an aperture in the spring drum and second bore there, whereby the spring urges the flexible lead longitudinally away from the fuse tube.

United States Patent 1 Cooper Apr. 29, 1975 [75] Inventor: Robert LynnCooper, Creve Coeur,

[73] Assignee: International Telephone and Telegraph Corporation, NewYork, NY.

221 Filed: Jan. 25, 1974 211 Appl.No.:436,648

[56] References Cited UNITED STATES PATENTS Lindell 337/l77 PrimaryExaminer-Thomas H. Eager Allorney, Agent, or Firm-J B. Raden; W. J.Michals [57] ABSTRACT A fuse extractor assembly for use with a fuse linkhaving a flexible lead extending therefrom and wherein the fuse link ismounted within a fuse tube. The assembly includes a base member fixedlysecured to one end of the fuse tube and having an opening therein sothat the flexible lead extends from the fuse tube through the opening.An extension rod slidably engages the base member in a first boretherein, and extends longitudinally of the fuse tube. A flat spring isfastened at one of its ends to a spring drum and wound thereabout. Theother end of the spring is fastened to the extended end of the extensionrod. The flexible lead is fed through an aperture in the spring drum andsecond bore there, whereby the spring urges the flexible leadlongitudinally away from the fuse tube.

10 Claims, 16 Drawing Figures mgrngmmzsmzs 3.879.833 sum 5 of FIG. 11

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1 FUSE EXTRACTOR FOR USE WITH FUSE LINKS HAVING A FLEXIBLE LEADEXTENDING THEREFROM BACKGROUND OF THE INVENTION This invention relatesto an enclosed, non-vented expulsion fuse structure and, moreparticularly, to a fuse structure suitable for use with universal fuselinks.

In the prior art, expulsion fuses such as overhead fuse cutouts are wellknown. In its simplest form, the overhead fuse cutout can be consideredas a meltable, weaklink fuse installed in a relatively long tube linedwith an organic material such as horn fiber. Upon sensing an abnormalcondition in current, such as an overload or high-current fault, thelink melts or blows, and an are forms in the resulting gap. The normalenergy loss from the arc is sufficient to decompose a portion of theorganic liner into a high-pressure, highly turbulent gas which acts onthe core of the arc to sufficiently cool and de-ionize the arc gas, and,thusly, effect circuit interruption at a current zero. The resultinghighenergy, high-pressure gas is expulsed into the atmosphere in a loud,explosive and luminous cloud.

The violent operating characteristics of expulsiontype distributionfuses and cutouts are not only environmentally objectionable for manyoverhead applications, but also effectively preclude the use of anexpulsion-type fuse in underground power distribution systems. That is,for underground distribution applications, the fuse must generally beinsulated during operation for safety considerations as well ashermetically sealed to protect it from its environment. However,presently known underground such as, for example, current-limiting fusesand oil-filled fuses fail to provide the standardized time-currentcharacteristics afforded by overhead cutout fuses. Accordingly, thepresent practice in the art of underground distribution systems is toprovide pole-mounted overhead cutout fuses at periodic locations alongthe underground distribution system. This practice obviously does notprovide a completely underground distribution system.

The present invention overcomes the problems and disadvantages of priorart fuses by providing an enclosed, non-vented expulsion fuse suitablefor use with universal fuse links having, for example, standard NEMA Kand T time-current characteristics. Accordingly, the expulsion fuse, inaccordance with the present invention, is suitable for use inunderground distribution systems, sub-surface and submersedapplications, and those applications where a non-violent operating fuseis required.

SUMMARY OF THE INVENTION Briefly, the present invention provides a fuseextractor for use with a fuse link of the type having a flexible leadextending therefrom, wherein the fuse link is mounted within a fuse tubeand where the extractor removes the flexible lead from the fuse tubewhen the flexible lead separates from the fuse link. The extractorcomprises a base member adapted to engage one end of the fuse tube andhaving an opening through which the flexible lead is extended from thefuse tube. An extension member engages the base member and extendslongitudinally of the fuse tube. A spring is fastened at one of its endsto the extended end of the extension member, and slidably engages theflexible lead at its other end. Means are provided for fastening thefree end of the flexible lead to the base member so that the springurges the flexible lead away from the fuse tube. In a preferredembodiment, the extension member comprises an extension rod whichslidably engages the base member in one of two bores provided therein.

BRIEF DESCRIPTION OF THE DRAWING The advantages of this invention willbecome more readily appreciated as the same becomes better understood byreference to the following detailed description when taken inconjunction with the accompanying drawing wherein:

FIG. I is a top view of an outdoor tank which serves as a housing forthe fuse structure in accordance with the present invention;

FIG. 2 is a side view of the tank of FIG. I;

FIG. 3 is a side view of the tank cover showing the relative mountingposition of the stationary element and loadside universal bushing well;

FIG. 4 is a side view of the load-side universal bushing well of FIG. 3.

FIG. 5 is a side view of a preferred fuse module in accordance with thepresent invention;

FIG. 6 is a partial cross-section of the fuse module of FIG. 5;

FIG. 7 illustrates a partial cross-section of the removable fusecartridge and fuse holder assembly of the fuse structure in accordancewith the present invention;

FIG. 8 is a partial cross-sectional view of the portion of thestationary element of the fuse module which is mounted to the tankcover;

FIG. 9 is a cross sectional view taken along the line 9-9 of FIG. 7 andillustrating the means by which the torque tube of FIG. 7 is removablymounted to the fuse holder assembly of FIG. 7;

FIG. I0 is a partial cross-section view of the fuse holder of theremovable fuse bushing well of the present invention;

FIGS. II and 12 provide top and cross-section views of the fuse tube capof the fuse holder of FIG. 10;

FIG. I3 is a partial cross-sectional view of a universal fuse linkadapted with a link extension assembly;

FIG. I4 is a partial cross-sectional view of the latch assembly of thefuse holder assembly of FIG. 10 and illustrating particularly theflexible lead connection and extractor spring features of the presentinvention;

FIG. 15 provides a bottom view of the latch of FIG. I4; and,

FIG. 16 is a cross-sectional view of the pressure container portion ofthe stationary element of the fuse module as taken along the line 16-16of FIG. 6.

DETAILED DESCRIPTION Referring now to FIGS. 1 and 2, there is showngenerally at 10 a hermetically sealed tank having a drum l2 and a topcover 14. Tank I0 provides a housing for the enclosed, non-ventedexpulsion fuse structure in accordance with the present invention.Mounted on cover 14 and projecting within drum 12 are a load-sideuniversal bushing well 16 and a fuse module shown generally at 18. Theportion of fuse module 18 which projects externally of tank 10 providesa universal bushing well having a recess essentially identical to thatof the universal bushing well recess of bushing, well 16. Bushing well16 is provided with a threaded projecting stud 16a, and fuse module 18is similarly provided with a threaded projecting stud 18a. Threadedstuds 16a and 18a provide means for attaching external bushing terminalsfor use with terminators such as an elbow as is well-known in the art.Top cover 14 is provided with conventional lifting eyes 20, threadedgrounding pads 22, and parking stand brackets 24. Pads 22 provideconnectors for securing the concentric ground leads of the associatedpower distribution lines, and brackets 24 provide means for convenientlystoring the associated elbow connectors, etc., when the fuse structureis being serviced. Top cover 14 is provided with a name plate 26, anddrum 12 is provided with mounting handles 28.

The upper bushing well portion of fuse module 18 includes a bushing wellcap 30 having an interlocking handle 32 pivotally mounted thereon aboutpins 340 and 34b. As discussed more fully hereinafter, handle 32 servesto latch cap 30 into its sealed position with respect to tank and thecooperating structure of fuse module I8. Handle 32 also serves as asafety interlock feature in that the associated line terminalconnections must be removed from bushing wells 16 and 18 before handle32 may be raised in such a position so as to permit withdrawal of fusemodule 18 from tank 10.

Referring now to FIG. 3, there is shown a side view of tank cover 14showing the relative mounting position of loadside bushing well 16 andfuse module 18. FIG. 3 also illustrates the construction of a stationaryelement 34 of fuse module 18. The upper portion 36 of stationary element34 is suitably mounted and hermetically sealed to top cover I4 at aflatened portion thereon. Upper portion 36 preferably takes the form offilament wound fiberglass or any other suitable insulating materialhaving adequate strength to support the internal assembly of fuse module18. The lower portion of stationary element 34 comprises a pressurecontainer 38. Pressure container 38 is preferably formed or cast from asuitable material such as aluminum. As will be discussed more fullyhereinafter, pressure container 38 conductively engages the lowerterminal of the associated fuse link and thereby provides means forcompleting the fuse circuit within drum I2 of tank 10 as by way of strap40. Strap 40 is coupled to pressure container 38 by way of a suitablefastening means 42, and coupled to the lower projection of bushing well[6 as by way of a suitable fastening means shown generally at 44.Bushing well 16 also includes a cylinder shield 46 which is suitablybonded or secured to top cover 14 and encloses the insulator portion ofbushing well 16. Shield 46 comprises rubber or any other suitableinsulating material and serves to increase the dielectric or withstandvoltage strength between top cover 14 and strap 40.

Referring now to FIG. 4, there is shown a side view of bushing well 16and illustrating particularly the conductive feedthrough member 160' andrecessed well 1612. It can be seen that bushing well 16 provides aconductive path from the outer surface of tank 10 to strap 40 by way ofstud 16a and member 160'.

Turning now to FIG. 5, there is shown a side view of fuse module 18illustrating particularly the structural features of interlocking handle32 and stationary element 34. Handle 32 further includes roller shafts48a and 48b upon which rollers 50a and 50b are disposed. Rollers 50a and50b slidably engage tongues 52a and 52b respectively. As handle 32 ispushed downwardly into the position shown in FIG. 5, bushing well cap 30is forced downwardly onto the uppermost portion of stationary element34. An O-ring (not shown in FIG. 5)

provides a gas-tight seal between stationary element 34 and bushing wellcap 30 when handle 32 is in its position as depicted in FIG. 5.

Referring now to FIG. 6, there is shown a partial cross-sections view offuse module cross-section and illustrating particularly the removablefuse bushing well 60 mounted therein. The removable fuse cartridge 60 isindependently illustrated in FIG. 7. As illustrated in FIG. 7, fusecartridge 60 comprises handle 32, bushing well cap 30, a torque tube 62,a latch 64, and a strainer assembly 66. Fuse cartridge 60 furtherincludes a conductive garter spring 68 and a rubber O -ring 70. Torquetube 62 is fixedly secured to bushing well 60, and removably secured tolatch 64 by way of a spring clip 72. That is, the upper portion oftorque tube 62 is positioned via four equally spaced grooves 74 whichengage corresponding tongues of bushing well cap 30 and is suitablybonded thereat; and, the inwardly projecting portions of spring clip 72engage the lower portion of torque tube 62 and a corresponding openingin the upper portion of latch 64. As described more fully hereinafter,latch 64 includes latch lugs 64a and 64b (not shown in FIG. 7).

One function of torque tube 62 is to transfer the torque or torsionprovided by handle 32 to latch 64. Referring to FIG. 9, there is shown across-section view of fuse cartridge 60 as taken along the line 9-9 ofFIG. 7. It can be seen that spring clip 72 is provided with two inwardlyprojecting end portions which function to removably secure torque tube62 to latch 64. Once spring clip 72 is removed from torque tube 62,latch 64 is free to be removed from fuse cartridge 60.

As illustrated in FIG. 10, latch 64 forms part of a fuse holder assembly80. It can be seen that latch '64 is provided with a central bore havingthreads which engage and are suitably bonded to one end of a fuse tube82. The other end of fuse tube 82 threadedly engages and is similarlybonded to end fitting 84, which in turn, threadedly engages fuse tubecap 86. A fuse tube cap 86 is provided with a conductive garter spring88. The uppermost portion of fuse tube cap is provided with torque meanssuch as a hexagonal nut head 86'.

Fuse holder further includes a fuse link extender 90 having a threadedportion which engages extension link top 92. The lower portion of linkextender 90 includes a threaded bore which engages a correspondingthreaded member of a universal fuse link as described more fullyhereinafter.

Fuse tube 82 preferably takes the form of filament wound fiberglass orany other suitable insulating material having sufficient strength tosupport the associated members of fuse holder 80. Fuse tube 82 includesa tube liner 94 of arc-responsive material such as vulcanized fiber orhorn fiber. Tube liner 94 is areresponsive in that energy loss from anassociated arc drawn within fuse tube 82 decomposes a portion of tubeliner 94 into a turbulent, high-pressure, hightemperature gas.

Still referring to FIG. 10, it can be seen that the lower portion oflatch 64 is provided with a suitable threaded portion which engagescorresponding threads on the inner portion of strainer assembly 66.Latch 64 also includes an Allen setscrew 64' disposed in a suitable boreof latch 64 as best shown in FIG. 15. This bore communicates with asecond longitudinal bore 65 provided in latch 64 which receives theflexible lead of the associated fuse link. Setscrew 64' is provided witha suitable surface such as a half-dog point to thereby secure theflexible lead of the associated fuse link in bore 65 of latch 64, and toprovide good electrical contacts between the flexible lead and latch 64.

Referring to FIGS. 11 and I2, there are shown top and cross-sectionalside views of fuse tube cap 86, of FIG. 10. It can be seen by referenceto FIG. 12 that fuse tube cap 86 is provided with a threaded portion 86aand an unthreaded portion 86b. In FIG. 13 there is shown a universalfuse link I00 assembled with fuse link extender 90 and extension linktop 92. In currently preferred practice, link top 92 is securedlyfastened to link extender 90 as by staking the male threads of linkextender 90 as shown in FIG. 13. The outer threads of link top 92correspond to the inner threads 86a of fuse tube cap 86. The assemblycomprising link top 92 and link extender 90 is advanced into fuse tubecap by rotating the assembly in the usual manner. Once link top 92clears thread 860, the assembly is free to swivel within fuse tube cap86. This swivel feature permits fuse tube cap 86 to be tightened ontofuse tube 82 without imposing shear stresses or torsional forces on fuselink 100. In currently preferred practice, the threads of link top 92are deformed, such as by staking, after link top 92 has been advancedinto portion 866 of fuse tube cap 86. This provision serves to preventremoval of fuse link extender 90. Hence. the possibility of installing afuse link without extender 90 is avoided. The function of a fuse linkextender is known to the art as exemplitied in U.S. Pat. No. 2,816,979.

Referring again to FIG. 7, it can be seen that the assembled fuseholder, as depicted in FIG. 10, is united with bushing well cap 30 byway of torque tube 62 and fastened therewith by way of spring clip 72.Further, the assembly depicted in FIG. 7 is united with stationaryelement 34 of FIGS. 3, 5, and 6 by inserting fuse cartridge 60 throughthe upper opening of stationary element 34 and sealingly engaging ittherewith by rotat ing safety interlock handle 32 until latch 64 locksinto place with pressure container 38.

It can be seen by reference to FIG. 8 that the upper portion ofstationary element 34 is provided with an outer annular groove 102 whichcarries an O-ring I04. Accordingly, when bushing well cap 30 of fusecartridge 60 engages stationary element 34, a relatively gas-tight sealis provided between stationary element 34 and bushing well cap 30 at theannular groove provided in the uppermost portion of stationary element34. FIG. 8 also illustrates an electrical stress relief surface I06provided on that portion of stationary element 34 which engages thesurface of tank cover 14. Stress relief surface I06 increases thedielectric or withstand voltage rating of the fuse structure inaccordance with the present invention.

Referring again to FIG. 6, it can be seen that when fuse module I8 iscompletely assembled, garter spring 88 of fuse holder 80 engages abushing contact insert 108 of bushing well cap 30. Projection stud 18aand bushing contact insert I08 are preferably provided as an integralunit. Accordingly, a conductive path is provided between threadedprojection stud 18a and fuse tube cap 86. Since fuse tube cap 86conductively engages the upper terminal of fuse link 100 by way of linkextender top 92 and link extender 90, a first line terminal connectionto fuse link 100 is thusly provided. It can also be seen that latch 64conductively engages pressure container 38 by way of garter spring 68.Since the flexible lead of fuse link 100 is fastened to latch 64 by wayof Allen screw 64, it can be seen that a second line terminal connectionto fuse link 100 is provided by way of fastener means 42, strap 40, andbushing I6.

Still referring to FIG. 6, it can be seen that O-ring provides a sealbetween the lower portion of fuse holder and pressure container 38.Accordingly, fuse holder 80 is substantially enclosed except at a loweropening thereof, and the lower opening is closed into a substantiallyenclosed chamber defined by pressure container 38. As discussed morefully hereinafter, pressure container 38 is provided with a pressurerelief fitting IIO having an aperture I12 which communicates with theenclosed volume of pressure container 38.

Disposed within pressure container 38 is a thermal quenching medium 114which rests upon vertical members 116. As discussed more fully in theco-pending application of G. L. Schurter, Ser. No. 436,644, filed Jan.25, I974, quenching medium I14 may comprise any one of a number ofsuitable media or materials. For example, quenching medium 114 maycomprise copper, steel or other suitable metal, screen rolled incylindrical form, without a plating or with a nickel or paladium platingthereon. Members 116 function to raise quenching medium 114 from thelower-most portion of pressure container 38. That is, in the operationof the fuse structure in accordance with the present invention, it hasbeen found that the greatest heat is experienced in the lower-mostportion. Accordingly, to avoid the possibility of unnecessary damage ormelting of quenching medium II4, members 116 effectively raise medium114 from the concentrated heat portion of pressure container 38.

Referring now to FIG. 14, there is shown a partial cross-sectional viewof latch 64 of fuse holder 80, and illustrating particularly theflexible lead connection and extractor spring features of the presentinvention. In FIG. 14, strainer assembly 66 has been removed in order toexpose extractor spring assembly I20. Spring assembly 120 includes aspring extension rod 122 and a constant force spring 124 which issecured at one end to rod 122 by way of a suitable fastening means 126such as a rivet. The other end of constant force spring 124 is confinedto spring drum 128 as by winding spring 124 about a recessed groove ofspring drum 128. Spring extension rod I22 slidably engages latch 64 atone of two bores A and B, provided therein. Bores A and B areillustrated more fully in FIG. 15.

Once the combination of fuse link I00, link extender and link extender92, as illustrated in FIG. 13, is installed in the uppermost portion offuse holder 80 at fuse tube cap 86, the flexible lead 101 of fuse linkprojects from the lower most portion of fuse tube 82. At this point theoperator or installer cuts the flexible lead 100 to the desired lengthand feeds the shortened flexible lead 101 through spring drum 128 andfastens same under screw 64'. The length of the shortened flexible leadI01 is selected so as to extend constant spring force 124 to its fulllength as illustrated in FIG. 14. In currently preferred practice, thespring constant of constant force spring 124 is selected so as toprovide approximately 8 lbs. of downward pressure on flexible lead 101.It will be appreciated by those skilled in the art that 8 lbs. ofpressure thusly provided is less than the maximum allowable stress on atypical universal fuse link.

The alternate bores provided in latch 64 permit the operator to selectalternate mounting positions for extension rod 122. Accordingly,regardless of which position extractor spring assembly 120 is installedin with respect to latch 64 and flexible lead 10], the operator ispermitted to install spring extension rod 122 at the nearest or mostconvenient bore in latch 64. Thus, spring drum 128 of extractor springassembly 120, when installed either as depicted in FIG. 14 or in areversed position, is effectively always conveniently located inrelative axial alignment with the central axis of fuse holder 80.

Referring now to FIG. 16, there is shown a crosssectional view ofpressure container 38 of fuse module 18 as taken along the line l6l6 ofFIG. 6. It can be seen by reference to FIG. 6 that pressure container 38is provided with projections 140 and 142 along its in side diameter,Projections I40 and 142 cooperate with latch pads 64a and 64b to securefuse cartridge 60 into stationary element 34. That is, once fusecartridge 60 is inserted into stationary element 34, fuse cartridge 60is rotated approximately 90 until latch lugs 64a and 64b are alignedbeneath projections 140 and 142. This feature provides a mechanicallysecure but removable means of fastening fuse cartridge 60 intostationary element 34. Whereas, however, the hermetic sealing functionis accomplished by way of O-ring 102 at the uppermost portion ofstationary element 34.

The operation of the fuse structure in accordance with the presentinvention is described as follows. It is assumed that the fuse structureis suitably connected between the line and load sides ofa powerdistribution system (not shown) by way of the universal bushing wellconnections at the surface of tank 10. Upon sensing an abnormalcondition in current, such as an overload or high current fault, thefusible member of fuse link 100 melts or is vaporized and an are formsin the resulting gap. The thermal energy loss from the are decomposes aportion of fuse tube liner 94 into a highpressure, high-temperatureturbulent gas which, in turn, acts on the core of the arc tosufficiently cool and de-ionize the gap and thus effect circuitinterruption at a current zero. At this time, flexible lead 101 of fuselink 100 drops out from fuse holder 80 either due to the resulting gaspressure, or as assisted by extractor spring assembly 120.

The expulsion of the gases from fuse holder 80 continues and, inaccordance with the present invention, impinges upon quenching medium114 in pressure container 38. As is explained in greater detail in theco pending application of G. L. Schurter, Ser. No. 436,644, filed Jan.25, I974, quenching medium 114 functions to extract thermal energy fromthe discharging gases at a rate sufficient to stop the thermal reaction.Once the reaction has been stopped and the circuit is totally cleared, aresulting residual pressure is present in pressure container 38.

In order to relieve this residual gas pressure and thereby avoidendangering an operator or installer in those cases where it is desiredto replace the fuse almost immediately after a fault occurs, pressurerelief assembly 110 is provided on a suitable surface of pressurecontainer 38. Accordingly, the residual gas pressure is graduallyrelieved until the gas pressure within the total enclosed volume of tank10 is reduced to a level which is determined by the relative volumes oftank 10 and pressure container 38.

Since the initial, residual high-pressure gas in pressure container 38can leak through fuse tube 82 of fuse holder into stationary element 34,stationary element 34 is provided with a pinhole 150 as depicted inFIGS. 3 and 5. Pinhole 150 also functions as a pressure relief openingso as to equalize any residual pressure in the upper portion ofstationary element 34. Thus, within minutes after a fuse clears, anoperator or installer can safely remove fuse cartridge 60 fromstationary assembly 34. At this time, the pressure within tank 10 inaccordance with currently preferred practice, will be typically equal toor less than 5 psig which is a manageable pressure level.

It should be noted, however, that when the resulting residual pressurein pressure container 38 is of the order of 30 psig, or greater, latchlugs 64a and 64b will be so tightly engaged with projections 140 and 142of pressure container 38, that rotation of fuse cartridge 60 iseffectively prevented. Accordingly, this feature affords operatorsafetyas the other-dangerous pressure must be relieved before fuse cartridge60 can be readily removed.

In a typical high-current fault operation, the gases discharged fromfuse tube 82 generally melt or destroy extraction spring assembly I20 aswell as flexible lead 101. Accordingly, strainer assembly 66, asdepicted in FIG. 7, is provided to collect the resulting debris. Anyresidual debris which does escape the screen material of strainerassembly 66 is prevented from blasting up into the upper portion ofstationary element 34 by way of rubber O-ring 70.

It should now be appreciated that once fuse link [00 does clear, it canbe conveniently replaced with a new fuse link by removing anddisassembling fuse cartridge 60. Once fuse cartridge 60 is removed fromstationary element 34, fuse holder 80 is removed from fuse cartridge 60by simply removing spring clip 72 at which time fuse holder 80 is freeto be removed from fuse bushing well cap 30. Once fuse holder 80 isremoved, strainer assembly 66 and fuse tube cap 86 are respectivelyremoved from their threaded engagement with fuse holder 80. At thistime, a new fuse link is installed onto link extension 90. In currentlypreferred practice, the button head cap of the universal fuse link isremoved and discarded, and the remaining threaded member is advancedinto link extender 90. The extended fuse link assembly is thenreassembled onto the upper portion of fuse holder 80. At this time, anew extractor spring assembly is also installed at the lower portion offuse holder 80 as described hereinbefore. The strainer assembly 66 isthen advanced onto the lower portion of latch 64, and fuse holder 80 isnow ready to be reassembled with the corresponding parts of fusecartridge 60. The assembled fuse cartridge 60 is then inserted intostationary element 34 and secured therein with a 90 rotation of handle32 as described hereinbefore.

It will be appreciated by those skilled in the art that fuse cartridge60, in accordance with the present invention, serves a plurality offunctions. For example, the assembly provided by fuse cartridge 60functions to transfer torque or torsion from handle 32 to the latchmechanism comprising latch 64 of fuse holder 80, and projections and 142of pressure container 38. Fuse cartridge 60 also functions to provide,at the bushing well cap 30, a hermetic seal between the outsideenvironmnet of the fuse structure and the fuse structure itself.Additionally. fuse cartridge 60 provides a current transfer terminal orconnection for the line-side of the fuse as at the recess in bushingwell cap 30.

Although the preferred embodiment of the invention as illustrated hereinincorporates a generally cylindrical fuse cartridge, it will beappreciated by those skilled in the art that other geometric forms andvariations may be indulged in within the scope of the appended claims.What has been taught. then, is a totally enclosed. nonvented expulsionfuse particularly suitable for use with universal fuse links andproviding non-violent expulsion fuse operation.

What is claimed is:

1. A fuse extractor for use with a fuse link having a flexible leadextending therefrom wherein said fuse link is mounted within a fusetube, and wherein said extractor removes said flexible lead from saidfuse tube when said flexible lead separates from said fuse link saidextractor comprising, in combination:

a base member adapted to engage one end of said fuse tube and whereinsaid flexible lead extends from said fuse tube at said base member;

an extension member having a first end engaging said base member andsaid extension member extending longitudinally of said fuse tube;

a spring having first and second end portions, said first end portionbeing fixedly mounted to the other end of said extension member and saidsecond end portion receiving said flexible lead; and,

means for fastening the free end of said flexible lead to said basemember wherein said spring urges said flexible lead longitudinally awayfrom said fuse tube.

2. The extractor according to claim I, wherein said spring includes aspring drum at said second portion thereof for receiving said flexiblelead, said spring drum having an aperture therein wherein said flexiblelead is fed through said aperture.

3. The extractor according to claim 2, wherein said base member includesat least two spaced-apart bores therein and extending longitudinally ofsaid fuse tube, and wherein said extension member comprises a rod whichengages said base member at one of said bores.

4. The extractor according to claim 3, wherein said means for fasteningsaid free end of said flexible lead includes a first bore in said basemember for receiving said flexible lead.

5. The extractor according to claim 4, wherein said base member includessecond and third spaced-apart bores therein and extending longitudinallyof said fuse tube, and wherein said rod engages said base member at oneof said second and third bores.

6. The extractor according to claim 5 wherein said extension rodslidably engages said base member.

7. The extractor according to claim 3, wherein said extension rodslidably engages said base member.

8. The extractor according to claim I. including means for swivelmounting said fuse link at the other end of said fuse tube wherein saidfuse link is free to totate about a longitudinal axis of said fuse tube.

9. The extractor according to claim 1, further including a strainerhousing removably mounted to said base member and enclosing saidextractor at said one end of said fuse tube.

10. The extractor according to claim 1, wherein said base memberincludes latch means for removably mounting said extractor and said fusetube to an external cooperating housing.

1. A fuse extractor for use with a fuse link having a flexible leadextending therefrom wherein said fuse link is mounted within a fusetube, and wherein said extractor removes said flexible lead from saidfuse tube when said flexible lead separates from said fuse link saidextractor comprising, in combination: a base member adapted to engageone end of said fuse tube and wherein said flexible lead extends fromsaid fuse tube at said base member; an extension member having a firstend engaging said base member and said extension member extendinglongitudinally of said fuse tube; a spring having first and second endportions, said first end portion being fixedly mounted to the other endof said extension member and said second end portion receiving saidflexible lead; and, means for fastening the free end of said flexiblelead to said base member wherein said spring urges said flexible leadlongitudinally away from said fuse tube.
 2. The extractor according toclaim 1, wherein said spring includes a spring drum at said secondportion thereof for receiving said flexible lead, said spring drumhaving an aperture therein wherein said flexible lead is fed throughsaid aperture.
 3. The extractor according to claim 2, wherein said basemember includes at least two spaced-apart bores therein and extendinglongitudinally of said fuse tube, and wherein said extension membercomprises a rod which engages said base member at one of said bores. 4.The extractor according to claim 3, wherein said means for fasteningsaid free end of said flexible lead includes a first bore in said basemember for receiving said flexible lead.
 5. The extractor according toclaim 4, wherein said base member includes second and third spaced-apartbores therein and extending longitudinally of said fuse tube, andwherein said rod engages said base member at one of said second andthird bores.
 6. The extractor according to claim 5 wherein saidextension rod slidably engages said base member.
 7. The extractoraccording to claim 3, wherein said extension rod slidably engages saIdbase member.
 8. The extractor according to claim 1, including means forswivel mounting said fuse link at the other end of said fuse tubewherein said fuse link is free to rotate about a longitudinal axis ofsaid fuse tube.
 9. The extractor according to claim 1, further includinga strainer housing removably mounted to said base member and enclosingsaid extractor at said one end of said fuse tube.
 10. The extractoraccording to claim 1, wherein said base member includes latch means forremovably mounting said extractor and said fuse tube to an externalcooperating housing.